This is a proposal to describe the characteristics of smokers who quit on their own as compared to (a) smokers who quit in formal, organized groups, (b) smokers who have tried unsuccessfully to quit, and (c) smokers who have never tried to quit. We intend, for this purpose, to develop a structured questionnaire extracted from open-ended interviews conducted in an extensive pre-test. Our initial goal is to formulate a comprehensive model of the smoking cessation process and to describe characteristics related to that process. Our final goal is to assess the potential value of our model for the design of future smoking control programs.